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HIV/AIDS Study Offers New Clue to Developing an Effective Vaccine

A groundbreaking HIV/AIDS study led by Dr. Salim Abdool Karim of the Centre for the AIDS Programme of Research in South Africa (CAPRISA) and the Mailman School's Department of Epidemiology provides important new insights to the human antibody response to HIV, which could provide a key to making an effective AIDS vaccine. Dr. Karim and colleagues describe how changes in the outer covering of the virus found in two HIV-infected South African women triggered the production of potent antibodies able to neutralize a wide range of HIV strains.

For the past five years, Dr. Abdool Karim and the consortium at CAPRISA have been studying how a small subgroup of HIV-infected individuals develop very powerful antibody responses known as broadly neutralizing antibodies. The CAPRISA team initially discovered that two KwaZulu-Natal women, one of whom participated in the earlier CAPRISA tenofovir gel study, could make these rare antibodies. Antibodies isolated from one of the women, were able to neutralize 88% of a large panel of HIV viruses against which it was tested. The other woman’s antibodies neutralized 46%.

“Broadly neutralizing antibodies are considered to be the key to making an AIDS vaccine,” said Dr. Salim Abdool Karim, Director of CAPRISA and professor of clinical Epidemiology. “This discovery provides new clues on how vaccines could be designed to elicit broadly neutralizing antibodies. The world needs an effective AIDS vaccine to overcome the global scourge of AIDS.”

While the existence of broadly neutralizing antibodies against HIV has been known for years, such antibodies were only isolated about three years ago. How they were produced remained a mystery until Dr. Abdool Karim and his associates showed that they were trigged by a shift in the position of a glycan, or sugar, in the outer coating of the HIV virus.

The CAPRISA consortium, led by Professor Abdool Karim, involves scientists from the National Institute for Communicable Diseases (NICD) in Johannesburg, the University of KwaZulu-Natal, University of Cape Town and University of the Witwatersrand, and brings together several of South Africa’s leading laboratory researchers in AIDS with partners in the U.S. This research was funded by the South African government’s Department of Science and Technology, the U.S. National Institutes for Health (through the NIAID-funded Centre for HIV/AIDS Vaccine Immunology) and the Bill & Melinda Gates Foundation.